The present invention relates to a particle size distribution analyzer adapted for use in observing the health condition of microscopic particles, such as blood cells. More particularly, the invention relates to a particle size distribution analyzer adapted for use in examining a possible symptom of abnormality or disease of particles through electrical or optical differences between the particles and a medium, such as physiological salt solution, in which the particles are dispersed, wherein the dispersion medium is passed through a detection pore. The analysis is carried out by examining the pulse intervals and the pulse widths obtained in response to the particles passing through the detection pore.
It is known in the art that microscopic particles (hereinafter referred to merely as particles) are detected by their electrical or optical differences from the dispersion medium when the medium is passed through a pore in the detector. In such analytical processes it is essential to detect particles individually when they pass through the pore. In the known processes, however, it often happens that two or more particles simultaneously pass, or that several particles pass in linking states. It also happens that the particles become aggregate in places in the dispersion medium. Owing to these phenomena the intervals of generating pulses become irregular, which will result in misled data. Accordingly, to remedy this situation a special process is additionally required. The common practice is to sample an optional part of the signals, and record them in a high-speed digital recorder. Then, each recorded signal is called and displayed as a motionless waveform on an oscilloscope, from which waveforms data are read out by the use of a scale. Alternatively, a computer capable of arithmetic operation at a high speed is employed to analyze the signals directly.
However, these remedying methods have disadvantages; in the former method the range of obtaining data is considerably limited, and as a result, the obtained data can be deficient in facts or fail to reveal the truth. In addition, such after-treatment is time- and labor-consuming. In the latter method the pulse intervals range from a few microseconds to a few thousands of microseconds, so that the computer must be, for arithmetic operation, adapted for a few microseconds in such a vast range. A disadvantage is that much time is wasted in waiting from adaptation to adaptation, and that after all on average it covers only a few hundreds of microseconds.